That's a 4 plait bridle, about a half a hide, give or take depending how fancy. 8 plait bridle is about a hide, again, depending on the size of the hide and how fancy the bridle.
Reins are about a hide too. Those have a 4 plait kangaroo core then there are buttons under some of the buttons you see, so there is more leather there than it appears, and the strings for the buttons add up.
I'll post a couple more photos.